Hello! Your answer would be a gain of electrons and a decrease in positive charge.
Contrary to how it sounds, reduction is actually a gain of electrons. It is part of a set of reactions known as a redox reaction, reduction being a gain of electrons and oxidation being a loss.
With the gain of electrons, the element would become more negative as electrons bring with them a negative charge. Therefore, this would decrease the positive charge.
Hope this helped!
Answer: a)
and pH = 1.04
b)
and 
c)
and ![[OH^-]=1.41\times 10^{-4}](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D1.41%5Ctimes%2010%5E%7B-4%7D)
Explanation:
pH or pOH is the measure of acidity or alkalinity of a solution.
pH is calculated by taking negative logarithm of hydrogen ion concentration.
![pH=-\log [H^+]](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5BH%5E%2B%5D)
![pOH=-\log [OH^-]](https://tex.z-dn.net/?f=pOH%3D-%5Clog%20%5BOH%5E-%5D)

a) ![[H^+]=0.090M](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D0.090M)
![pH=-\log [0.090]=1.04](https://tex.z-dn.net/?f=pH%3D-%5Clog%20%5B0.090%5D%3D1.04)

![12.96=-log[OH^-]](https://tex.z-dn.net/?f=12.96%3D-log%5BOH%5E-%5D)
![[OH^-]=1.09\times 10^{-13}](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D1.09%5Ctimes%2010%5E%7B-13%7D)
b) ![[OH^-]=0.00098M](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D0.00098M)
![pOH=-\log [0.00098]=3.01](https://tex.z-dn.net/?f=pOH%3D-%5Clog%20%5B0.00098%5D%3D3.01)

![10.99=-log[H^+]](https://tex.z-dn.net/?f=10.99%3D-log%5BH%5E%2B%5D)
![[H^+]=1.02\times 10^{-11}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D1.02%5Ctimes%2010%5E%7B-11%7D)
c) 
![10.15=-\log [H^+]](https://tex.z-dn.net/?f=10.15%3D-%5Clog%20%5BH%5E%2B%5D)
![[H^+]=7.08\times 10^{-11}](https://tex.z-dn.net/?f=%5BH%5E%2B%5D%3D7.08%5Ctimes%2010%5E%7B-11%7D)

![3.85=-log[OH^-]](https://tex.z-dn.net/?f=3.85%3D-log%5BOH%5E-%5D)
![[OH^-]=1.41\times 10^{-4}](https://tex.z-dn.net/?f=%5BOH%5E-%5D%3D1.41%5Ctimes%2010%5E%7B-4%7D)
Hello!
To find electron configuration for Idoine we need to understand the following steps:
- Finding the Atom's Atomic Number (tells us the specific number of electrons)
- Determining the Charge of the Atom
- Understanding the orbitals (Set S [Contains 2], P [Contains 3, Holds 6], D [Contains 5, Holds 10], F [Contains 7, Holds 14], and there are some theoritical ones.) [Overall the sets go SPDFGHIK
- Understanding notations in configuartion. The notations display the number of electrons in the atom and set.
In this case, for Iodine. If we follow these rules we can see that the electron configuration is [Kr] 4d^10 5s^2 5p^5. We use Krytpon in front because that is the last full and stable noble gas before this particular element. Atoms are just trying to be stable so the goal is to achieve that full shell.